Amazing bokeh, sharp at wide apertures, great contrast and colors, fast focus even in low light

Cons:

Heavy, distortions in the corners on full frame body, pricey

This was the first lens I bought after getting my first DSLR. I looked at this, the Canon 50mm f/1.8, and the Canon f/1.4. While this lens costs $100 more than the Canon f/1.4 and more than twice as much as the f/1.8, I couldn't help but fall in love with the heft and solid feel of the Sigma lens. The image quality has proved to be consistently amazing and despite having a larger lens collection now, this is still the one that I reach for by default. It's as sturdy as it feels, surviving regular abuse. While there are tales of focus issues, my copy has been pretty well spot on, even wide open.

You honestly don't need to worry about leaving this lens wide open to shoot with, although it does improve slightly at around f/2.0. Plus, with a cropped frame sensor, it makes for a great short portrait lens.

It's not weather sealed like some L lens, but the optics and build are of L quality. Plus, you get a hood and a nice lens case, which would cost you at least the $100 difference between this and the Canon f/1.4 model. If you're going to pair this with a Canon Rebel series, it balances much better with a battery grip attached, otherwise the camera almost feels dwarfed.